JPH08332727A - Ink jet recording head and apparatus - Google Patents

Abstract

PURPOSE: To obtain an ink jet recording apparatus having gradation control function and excellent in recording grade. CONSTITUTION: The heater being the electrothermal conversion element provided on an ink jet recording head and heating and foaming ink to emit the same from orifices has large and small heaters 3, 4 per one orifice 40 and the distance between the large heater 3 and the orifice 40 is larger than the distance between the small heater 4 and the orifice 40 and the large heater 3 can be selectively driven by electrode wiring 6 and the small heater 4 can be selectively driven by electrode wiring 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head for ejecting ink toward a recording medium by inputting an electric signal, and an ink jet recording for recording characters and images on the recording medium by mounting the ink jet recording head. It relates to the device.

[0002]

2. Description of the Related Art In various devices such as computers, word processors, facsimile machines, copying machines and printers,
As a means for recording on a recording medium such as paper, an inkjet recording apparatus is being widely used because it can perform high-speed recording without generating noise and can easily record a color image.

An ink jet recording head provided in an ink jet recording apparatus is a member for ejecting ink from a position facing the recording medium by inputting a signal current from the ink jet recording apparatus to record characters, images and the like on the recording medium. Therefore, the ink is ejected by the thermal energy generated by the signal current from the inkjet recording device.

FIG. 8 is a schematic perspective view of the ink jet recording head, and FIG. 9 is a schematic sectional view of the ink jet recording head.

Reference numeral 40 is an orifice which is an ejection port for ejecting ink, 41 is a first substrate, 41a is an electrothermal conversion element installed on the first substrate 41 to heat and foam ink, and 42 is a second substrate and 42a. Is an ink flow path, 42b is an ink chamber, and 42c is an ink supply port.

As shown, the first substrate 41 and the second substrate 4
2 are joined to form an ink channel 42a and an ink chamber 42b, and ink is supplied from the ink supply port 42c to the ink chamber 42b and the ink channel 42a.
An electrothermal conversion element (hereinafter referred to as a heater) 41a provided in the portion a generates heat by a signal current supplied from a current supply unit of the inkjet recording apparatus, and the ink flow path 42a.
The ink inside is foamed by heating, and the foaming causes the ink in the ink flow path 42a to be ejected from the orifice 40 toward the recording medium.

In order to control the density gradation of ink jet recording, a plurality of heaters are provided for one orifice, and a functional element circuit for supplying signal electricity to each heater is provided in the first substrate, There is known a configuration capable of imparting gradation to a recorded image by selectively supplying signal electricity to each heater to change the amount of ink ejected for one pixel.

[0008]

However, in the conventional configuration, a plurality of heaters having different heater areas are arranged in parallel in an ink flow path (hereinafter referred to as a nozzle) for one orifice, and the plurality of heaters are simultaneously foamed. If the distance between the orifice heaters is set so that the discharge amount and image quality are stable when the ink is discharged, the distance between the orifice heaters becomes too long when driving a heater with a small area independently, and the power for discharging the ink is insufficient. May not be ejected as a droplet. Therefore, the heater having the smallest area within one nozzle cannot perform stable ejection, the gradation becomes unstable, and the printing quality deteriorates.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus which have a gradation control function and are excellent in recording quality. To do.

[0010]

Therefore, in the ink jet recording head according to the present invention, the ejection port forming portion for sending the ink to the orifice for ejecting the ink, and the heat energy generated by the electric signal input to the inside of the ejection port forming part. An ink jet recording head having a substrate provided with an electrothermal conversion element for heating and bubbling the ink of the above, and ejecting the ink from the orifice, wherein the electrothermal conversion element is in an ejection port forming portion for ejecting the ink from one orifice. In addition, a plurality of electrothermal conversion elements that can be individually driven by inputting electric signals are provided at different distances from the orifice. The plurality of electrothermal conversion elements provided in the ejection port forming portion for ejecting have different areas for heating the ink. With the configuration, characterized in that there is intended to achieve the above object.

The ink jet recording apparatus according to the present invention is
Recording is performed by selecting and driving a plurality of electrothermal conversion elements provided in the ejection port forming portion that includes the inkjet recording head and ejects ink from the one orifice, and ejects the ink to the recording medium. The above-mentioned object is to be achieved by the constitution characterized by the above.

[0012]

With the above structure, by arranging a plurality of heaters having different areas in one nozzle at a distance between orifice heaters capable of stable discharge, stable discharge can be performed even if the areas of the plurality of heaters are different. Therefore, it is possible to stably change the amount of ink to be ejected per pixel, and it is possible to provide high quality gradation.

[0013]

EXAMPLES An ink jet recording head and an ink jet recording apparatus according to the present invention will be described by way of examples.

The embodiment of the present invention has a structure similar to that of the conventional ink jet recording head, and the electrothermal converting element generates heat by an electric signal supplied to the ink jet recording head from the current supply means of the ink jet recording apparatus, and the ink The ink in the flow path is heated and foamed, and the foaming causes the ink in the ink flow path to be ejected toward the recording medium from the orifice (ink ejection port) facing the recording medium to record characters, images, etc. It is configured to do.

Further, the embodiment is characterized in that it has a plurality of electrothermal conversion elements for one orifice, and that high-quality recording control can be performed. , The effect will be described in detail.

(Embodiment 1) FIG. 1 is a schematic view showing an arrangement of electrothermal conversion elements on a substrate of an ink jet recording head which is Embodiment 1 of the present invention, and FIG. 2 is an electrothermal conversion element of Embodiment 1. It is a schematic diagram which shows the electrode wiring of.

In one discharge nozzle between the nozzle walls 5, two heaters, a large heater 3 and a small heater 4, are arranged at different distances to the orifice 40. Each of the heaters 3 and 4 is connected via a through hole 2 to a common wiring 1 under the interlayer insulating film below the heater, and a voltage is applied from the common wiring 1.

The wirings 6 and 7 are respectively connected to the large heater 3 and the small heater 4 and the switching transistors 10 and 11 through through holes 16. The switching transistors 10 and 11 are also arranged under the heater and below the interlayer insulating film. Further, turning on and off the transistors 10 and 11
Signal lines 17 and 18 are connected to the transistors 10 and 11 and the shift register / latch circuits 19 and 20 to control the FF.

With the above configuration, the drive data of the heater is fetched by the shift register / latch circuits 19 and 20 to control the transistors 10 and 11 to be turned on and off. The ground wirings 12, 13, 14, and 15 are connected to the emitters of the switching transistors 8, 9, 10, and 11, respectively.

FIG. 3 is a schematic view showing the structure of the entire substrate of the first embodiment.

The substrate 23 is constituted by a continuous arrangement of cells 25 constituting the common wiring 1 shown in FIGS. The common wiring 1 is connected to the contact 24 by the common vertical wiring 23,
Receives power from an external power source. Ground wiring 12, 1
3, 14, 15 are connected to the contact 24 by a ground vertical wiring 21.

Equivalent circuits of the configurations shown in FIGS. 1, 2 and 3 are shown in FIGS.

In FIG. 4, the shift register / latch circuit 1 is shown.
9 and 20 are shown in detail. A clock signal line 37 and a serial data line 35 are connected to the shift register 36, and serial data is transferred to the shift register 36 by a clock signal. The data input to the shift register 36 is held in the latch 33 by the latch signal from the latch signal line 34. Next, the enable signal 32 is AN
It is connected to the D gate 31 and inputs a timing signal for applying the data of the latch 33 to the transistor 11.
Since there are two enable signals 32, the heaters 3 and 4 can be driven simultaneously or at different timings.

FIG. 5 is an equivalent circuit diagram of the entire structure of the substrate 23 in which the cells shown in FIG. 4 are continuously arranged.

FIG. 5 shows a decoder 38 and a decoder signal line 39.
This is for controlling the driving timing in various ways, and many timings can be driven with a small number of contacts without having a plurality of enable signals 32.
The basic timing chart of these is shown in FIG.

Next, the stable control of the ink ejection amount using the substrate 23 will be described.

The discharge nozzle sandwiched by the nozzle wall 5 is filled with ink, and when the large heater 3 and the small heater 4 are heated to foam, the ink is discharged from the orifice 40 by the foaming pressure.

However, in general, in the case of a large heater,
If the heater / orifice distance is made too short, the ink between the heater / orifice is insufficient for the amount of ink to be ejected, resulting in faint recording. Further, in the case of a small heater, if the heater / orifice distance is made too long, the foaming force for ejection may be insufficient with respect to the ink viscosity resistance between the heater / orifice, and the droplets may not be ejected.

Therefore, the distance between the orifices and the heaters of the large heater 3 and the small heater 4 is set to a distance at which the discharge is stable, and moreover, gradation can be obtained even if the large heater 3 and the small heater 4 simultaneously foam. By setting the distance between the orifice and the heater that can achieve, a stable discharge amount can be obtained regardless of whether the large heater 3 and the small heater 4 are driven simultaneously or simultaneously. Therefore, for example, by providing x kinds of heaters, High quality 2 ^x gradation can be realized.

(Embodiment 2) FIG. 7 is a schematic view showing the arrangement of the electrothermal conversion elements (heaters) of Embodiment 2.

In the second embodiment, since the large heater 3 and the small heater 4 are arranged in series, the center of ink bubbling by the large heater 3 and the small heater 4 occurs at the center of the nozzle, so that the ink is ejected. Is efficiently foamed. Then, by setting the large heater 3 and the small heater 4 at a distance at which each discharge amount is stable, high-quality gradation control is possible.

(Other Embodiments) In the embodiment of the ink jet recording apparatus according to the present invention, the ink jet recording head of the first embodiment or the second embodiment is mounted and ink is ejected from the ink ejection port based on the image signal. As described in the above embodiment, high-quality gradation control is performed by selectively driving large and small electrothermal conversion elements. Can be recorded.

[0033]

As described above, according to the present invention,
High-quality image gradation control can be performed by setting the orifice / heater distance for each heater that enables stable ejection to a plurality of heaters having different areas provided in one nozzle.

The gradation control can be performed without increasing the number of data pads, and since the number of pads does not increase, the reliability of the contact is improved, so that the gradation is stable and the ink jet recording head and the ink jet are excellent in printing quality. A recording device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a heater arrangement according to a first embodiment.

FIG. 2 is a schematic diagram illustrating a drive unit according to the first embodiment.

FIG. 3 is a layout view of a drive unit on a substrate according to the first exemplary embodiment.

FIG. 4 is an equivalent circuit diagram for driving the heater of the first embodiment.

FIG. 5 is an equivalent circuit diagram for driving the heater of the first embodiment.

FIG. 6 is a drive timing chart of the first embodiment.

FIG. 7 is a schematic diagram showing a heater arrangement of Example 2.

FIG. 8 is a schematic perspective view of a conventional inkjet recording head.

FIG. 9 is a schematic cross-sectional view of a conventional inkjet recording head.

[Explanation of symbols]

 1 common wiring 2 through hole 3 large heater 4 small heater 5 nozzle wall 6,7 electrode wiring 8, 9, 10, 11 switching transistor 12, 13, 14, 15 ground wiring 17, 18 signal wiring 19, 20 shift register latch Circuit 23 Substrate 40 Orifice

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiyuki Imanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (3)

[Claims] 1. A discharge port forming part for sending ink to an orifice for discharging ink, and an electrothermal conversion element for generating thermal energy by inputting an electric signal to heat and foam ink in the discharge port forming part to discharge from the orifice. An ink jet recording head including a substrate provided, wherein the electrothermal conversion element includes a plurality of electric elements that can be driven by individually inputting electric signals into an ejection port forming portion that ejects ink from one orifice. An ink jet recording head, wherein heat conversion elements are provided at different distances from an orifice. 2. The plurality of electrothermal conversion elements provided in the ejection port forming portion for ejecting ink from the one orifice have different areas for heating the ink from each other. Inkjet recording head. 3. The inkjet recording head according to claim 1 or 2, comprising: selecting and driving a plurality of electrothermal conversion elements provided in a discharge port forming portion for discharging ink from the one orifice. An ink jet recording apparatus, which ejects ink onto a recording medium to perform recording.